Jastrow proceeds to state that "Anu was originally the personification of some definite power of nature, and everything points to this power having been the sun in the heavens. Starting from this point of view we quite understand how the great illuminer of heaven should have been identified with the heavens in an artificially devised theological system, just as En-lil became in this system the designation of the earth and of the region above the earth viewed as a whole."[7] The very fact that in the earliest times Anu was identified with the expanse of the sky itself, and that the symbol used to denote him meant 'heaven,' is against this supposition. Again, the theory suffers from lack of analogy. In what other mythology is there to be found a sky-god who at one time possessed a solar significance? The converse might be the case. Some sky-gods have attained the solar connexion because of their rule over the entire expanse of the heavens, just as they have attained the power of wielding lightning and the wind. But we are at a loss to recall any deity originally of distinctive solar attributes who later took the position of a sky-god.
Anu was regarded as head of the triad and the father of En-lil. We are told that the goddess Aruru first shaped man in the image of Anu, who must thus have attained an anthropomorphic condition. He appears also to have been regarded as the conqueror of primeval chaos. His consort was Anatu, probably a later feminine form of himself.